Electromagnetic belay



April 3, 1951 s. H. TowNER ET AL ELECTROMAGNETIC RELAY Filed May 30, 1945 3 Sheets-Sheet 1 Attorney April 3, 1951 s. H. TowNER ET AL ELECTROMAGNETIC RELAY 5 Sheets-Sheet 2 Filed May 50, 1945 (mls.)

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Ingentor $cm1 Hamann hmmag gm www mugs April 3, 1951 Filed May 50, 1945 S. H. TOWNER ET AL ELECTROMAGNETIC RELAY 3 Sheets-Sheet 3 Harney Patented Apr. 3, 1951 ELECTROMAGNETIC RELAY Stanley Herbert Towner and Percy ArthurChilds,

London, England, assignors,.by mesne assignments, to International Standard 'ElectricCorporation, New York, N. Y., a corporation of Delaware Application May 30, 1945, Serial No..596,68(l In Great Britain April 28, .1944

Section 1, Public Law 690, August 8, 1946 Patent expires April Z8, 1964 3 Claims.

This invention relates to electromagnetic relays.

Among the objects of the in ention is that of providing a more robust design of electromagnetic relay, and especially a midget relay.

The following description relates to the accompanying drawings, in which:

Fig. l is a side-view of va complete relay in accordance with the present invention;

Fig. 2 is a side-view of the contact-spring-set assembly;

Fig. 3 is a left-hand end view of the spring-set assembly shown in Fig. 2;

Pig. 4 is an underneath plan view of the springset assembly shown in Fig. 2;

Fig. 5 is a top plan view of the armature;

Fig. 6 is a side view-of the armature;

Fig. '7 is a section on the line A-A of Fig. 5;

Fig. 8 is a left-hand end view of a relay, being a. modification; and

Fig. 9 is a similar view of a further modification.

The design of the relay is somewhat like that disclosed in the copending U. S. patent application Ser. No. 546,545, now Patent No. 2,501,157, June 6, 1950. The relay winding I is mounted upon a soft-iron core 2 of which the forward projecting end 3 is turned up and tiren back to form a polepiece 4 with its il'at uppermost surface constituting the vpole-face. Tightly fitting over, and riveted to, the'rearward'projecting end of the core '2 visa yoke 5 extending Vupwardly and forwardly along'the top of thewinding to within a short distance of the pole-piece 4.

The amature 6, which is `almost but not quite flat when viewed `edgewise (see Fig. 6), lies on the forward extension of the yoke 5 and bridges the gap between the yoke 5 and pole-piece'4.

Yliteferring to Fig. 5, an opening is cut away in the rearward half of the armature 6, leaving a frame-like tail 'I carrying the lifting pins 8 for engagement with the moving spring in the pileup. This tail I is bent slightly upwards with respect to the plane of the remainder of the armature (see Figs. 6 and 7). The bend between the forward and rearward halves of the armature is indicated in Fig. 5 by the line 9 on the upper side of the armature. Corresponding to this upper crease line, there is on the underside of the armature (see Figs. 6 and 7) a knife edge I0 which lies slightly below the level of the tail 'I and which therefore is able to constitute the pivot for the armature 6 as it rests upon the upper surface of the yoke 5 with its solid forward half overlying the pole-face on the pole-piece 4. Energization of the coil I causes the forward end of the armature 6 to be attracted downwardly to (Cl. G- 104) 2 the pole-piece .4, the armature turning about the knife-edge I so that the tail I rises and ythrough the intermediary of the lifting pins causes operation of the contacts. Thus the operating force and the Contact load are applied on opposite sides of tliepivot.

Referring now more particularly to Figs. 2, 3 and 4, together with Fig. l, it willbe seen that the springset is in two parts namely a root block I 1 carrying all of the springs l2 and a buffer block I3 supporting the upper and lower springs at their free ends where they carry the contacts I4. These two parts are assembled together by means of a small bracket I5 located above the yoke 5 and pole-piece 4 and belowthe buier block I3 and root block II.

The root block II is a thermo-setting plastic, and the springs I2 constituting the contact-spring pile-up have their roots moulded in the plastic in the manner disclosed in the copending U. S. patent application Ser. No. 611,410, now abandoned. The buffer block I3 is of ceramic material and calls for no special comment.

Whereas in the relay disclosed in the copending U. S. patent application Ser. No. 546,545, now Patent No. 2,501,157, June '5, 1950, already mentioned, the ilat armature is locatedby meansv of leaf springs extending normally across the pivoted axis Vand xed to the armature Yon one side of the first and to the yoke on the other side, in the embodiment of the present vinvention now being Vdescribedthe leaf spring is omitted, the armature B being loose and being located-by means of Slo-ts i6 in the armatureleading off from the opening in the, tail next to the knife-edge. These slots I5 are engaged by ears Ii' on the bracket I5' that mounts the root block I I and the buffer block I3 of the spring set assembly.

The root block II being moulded around the small bracket I5, and the'buffer block I3 being attached to the bracket by a fusing process. This whole assembly is then placed on the coil assembly and secured by a screw I8 passing down into the yoke 5. As an alternative the screw may be replaced by a pin xed in the yoke and secured by tin fusing to the ceramic at the top thus replacing the head of the screw by a tin fuse connection. This provides a complete design in which all parts are assembled without the use of screws and there is nothing to work loose under the conditions of vibration, shock, etc.

l As in the copending U. S. patent application Ser. No. 546,545, now Patent No. 2,501,157, June 6, 1950, already mentioned, the gravitational moments of the masses of the moving parts are sub- 3 stantially balanced about the pivot I0. That is to say, the mass of the front portion of the armature produces at the pivot a moment which is just about equal to the momentl produced by the mass of the tail part, together with the lifting pins, and the moving contact-springs down to their roots. By reason of this feature, a mechanical shock in the vertical direction (which is the worst case) produces equal and opposite accelerations about the pivot so that there is substantially no resultant torque that would cause improper operation or release of the armature.

As has been said above, it is one of the objects of this invention to provide a construction of relay which is resistant to adverse climatic conditions, especially the tropical conditions of highy temperature and high humidity. Actually the requirements which this invention seeks to satisfy extend far beyond that: it is desired to have a relay which shall stand up to a temperature ranging from 40 C. to {-100 C. with 100% humidity. It has been found by the present applicants that a source of failure in these extreme conditions lies with the lifting pins 8 when they are of the usual material; and they have therefore replaced this material by one more suitable, namely ceramic or vitreous material, or a thermosetting plastic, the pins 8 being secured to the armature E by cementing, fusing, moulding or other equivalent process.

An alternative arrangement for the mounting of the contact-spring pile-up in the root block I I is shown in Fig. 8, which is a view onto the lefthand or forward end of a. relay. Here" the root block I I is of ceramic material, and each contactspring I2 is located in or on the ceramic block II by being received on a flat surface I9 thereof, and by being embedded in a setting material 20 adhering both to the spring and to the block. Each such iiat is preferably overhung by adjacent portions 2l of the material on either side. The superficial extent of the bosses or the like between one flat and another and including the over-hanging function provides adequate insulation between the several springs.

In yet another alternative arrangement for the mounting of the contact-spring pile-up in the root block II, the root block is of ceramic, as in Fig. 8, but is of different shape. Reference to Fig. 9, which is a similar view to Fig. 8, shows the ceramic root block II formed with two serrated holes 22 through which the springs I2 eX- tend, being spaced and located by the serrations. When the springs have been inserted, the holes are iilled by an injection process with one of the klili relatively high temperature high insulating materials such as a synthetic resin or one of the self hardening materials such as plaster of Paris.

4 This filling completely encloses the spring root to exclude dust, moisture, etc.

What is claimed is:

1. An electromagnetic relay comprising a winding, a core extending through said winding andV having front and rear upturned portions, a forward extension on said rear upturned portion, an armature having a front end overlying said front upturned portion, said armature being pivoted at an intermediate point on said forward extension, a xed support overlying said armature and having integral projections thereon for positioning said armature thereto, spring mounting means on said support, a plurality of contact springs carried by said mounting means, and operating means on the rear end of said armature. engaging at least one of said contact springs in such manner that said contact spring tends to pivot said armature so as to lift said front end off said front upturned portion, energization of said winding acting to pivot said armature in the opposite direction.

2. An electromagnetic relay according to claim 1 wherein the gravitational moments of the masses of said armature, said operating means and the contact spring or springs engaged thereby are balanced about said intermediate point.

3. An electromagnetic relay according to claim 1 wherein the part of the armature to the front of said intermediate point is a solid piece of material and the part of the armature to the rear of said intermediate point is in the form of a frame-like tail.

STANLEY HERBERT T'OWNER. PERCY ARTHUR CHILDS.

REFERENCES CITED The followingn references are of record in the le of this patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date Great Britain Mar. 25, 1929 Number Number 

